Multi-configuration access ramp

ABSTRACT

An adjustable access ramp assembly includes at least one ramp unit that is adjustable between a plurality of positions relative to a platform. An integrated jack may be provided for adjusting the ramp unit. Two ramp units may be provided alongside each other in a switchback orientation with the platform. The ramp assembly can be configured for loading on a wheeled trailer unit to be hauled, and may include one or more stowed components to facilitate connection to a trailer hitch.

TECHNICAL FIELD

[0001] The present application relates generally to access ramps usedfor providing ramped access between two different elevations and, moreparticularly, to an adjustable access ramp that facilitates use innumerous settings to provided ramped access between a variety ofdifferent elevations.

BACKGROUND

[0002] It is common in many areas of the country to utilize modularbuildings such as trailer home style units at facilities needing extraspace in order to avoid the expense associated with constructing newspace at the facilities. In many situations the modular buildings mustbe ADA accessible, meaning that code compliant, ramped access must beprovided. In the past it has been common to “stick build” ramps at thesite where the modular building is placed, meaning that the necessaryramp is built out of wood, which typically requires the effort and timeof two men for 2 days or more. Another option that has been used in thepast is a modular style ramp where pre-built ramp sections are connectedtogether at the site in order produce the necessary ramp. However, suchmodular ramp systems are limited in their use at locations where theground is uneven, and such modular ramp systems still require asignificant amount of labor to install.

[0003] Accordingly, it would be advantageous to provide an access rampassembly that can be easily installed at different sites havingdifferent contours, and that can be adjusted to provide suitable rampedaccess at the different sites.

SUMMARY

[0004] In one aspect, an adjustable access ramp assembly for providingramped access between two elevations includes a frame and first andsecond amp units. The frame has a platform. The first ramp unit has afirst end adjacent to the platform and is movably mounted to the frameto permit a second end of the first ramp unit to be positioned either(i) above the platform such that the first ramp unit leads down to theplatform or (ii) below the platform such that that first ramp unit leadsup to the platform. The second ramp unit has a first end adjacent to theplatform and is movably mounted to the frame to permit a second end ofthe second ramp unit to be positioned either (i) above the platform suchthat the second ramp unit leads down to the platform or (ii) below theplatform such that that second ramp unit leads up to the platform.

[0005] In another aspect, an adjustable access ramp assembly forproviding ramped access between two elevations includes a frame andfirst and second ramp units. The frame includes a raised platform. Thefirst ramp unit includes a rampway having a first end positionedadjacent to the platform and a second end positioned away from theplatform, the first ramp unit movably mounted to the frame to enable itssecond end to move between a plurality of heights relative to theplatform while the first end of the rampway remains at a heightsubstantially the same as a height of the platform. The second ramp unitincludes a rampway having a first end positioned adjacent to theplatform and a second end positioned away from the platform, the secondramp unit movably mounted to the frame to enable its second end to movebetween a plurality of heights relative to the platform while the firstend of the rampway of the second ramp unit remains at a heightsubstantially the same as the height of the platform

[0006] In a further aspect, an adjustable access ramp assembly forproviding ramped access between two elevations includes a platform and aramp unit including a rampway surface having a first end positionedadjacent to the platform and a second end positioned away from theplatform, the ramp unit pivotally mounted to the platform. An integratedjack may also provided for moving one of the ramp unit and the platformto adjust an incline of the rampway surface relative to the platform.

[0007] In yet another aspect, a method of providing ramped accessbetween first and second different elevations involves the steps of:providing an adjustable access ramp assembly including a frame having araised platform, a first ramp having first and second ends, the firstramp movably mounted to the frame with its first end adjacent theplatform, and a second ramp having first and second ends, the secondramp movably mounted to the frame with its first end adjacent the rampplatform; positioning the adjustable access ramp assembly at a site ofthe first and second different elevations; adjusting the frame such thatthe raised platform is substantially level; moving the first ramp suchthat its second end is positioned lower than the platform and the firstramp leads up to the platform; and moving the second ramp such that itssecond end is positioned higher than the platform and the second rampleads down to the platform.

[0008] In still a further aspect, a method of providing ramped accessbetween first and second different elevations involves the steps of:providing an adjustable access ramp assembly including a frame having araised platform, and a ramp having first and second ends, the rampmovably mounted to the frame with its first end adjacent the platform;connecting the adjustable access ramp assembly to a wheeled trailer;hauling the adjustable access ramp assembly to the site using thewheeled trailer; disconnecting the adjustable access ramp assembly fromthe wheeled trailer at a site of the first and second differentelevations; adjusting the frame such that the raised platform issubstantially level. The ramp can then be adjusted as desired.

[0009] In another aspect, a trailer unit adapted for hauling an accessramp assembly and includes a frame including central part including aslot for receiving a lower part of an access ramp assembly I-beam. Achain system with associated hand crank is provided for use in engagingthe pulling the trailer unit and an access ramp assembly together.Spaced apart wheels are connected with the frame for allowing thetrailer unit to roll.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]FIG. 1 is a partial, exploded perspective view of one embodimentof an adjustable ramp assembly;

[0011]FIGS. 2A and 2B depict one installation configuration of the rampassembly of FIG. 1;

[0012]FIGS. 2C and 2D illustrate another installation configuration ofthe ramp assembly of FIG. 1;

[0013]FIG. 3 shows another embodiment of the a ramp assembly frame;

[0014]FIG. 4 shows a partial perspective of a corner section of a rampunit of the ramp assembly;

[0015]FIG. 5 shows a partial end elevation of the corner of the rampunit of FIG. 4;

[0016]FIG. 6 shows a partial perspective of a corner section of theplatform part of the ramp assembly of FIG. 1;

[0017]FIG. 7 shows a partial end elevation of a ramp unit engagingstructure on the platform to form a hinge;

[0018]FIG. 8 shows a hinge pin for a ramp unit;

[0019]FIG. 9 shows a partial cross-section of a ramp unit positionedadjacent to the platform;

[0020]FIG. 10 shows a partial perspective view of one embodiment of awheeled trailer unit for hauling a ramp assembly;

[0021]FIG. 11 shows a partial end elevation of a connecting part of thewheeled trailer unit;

[0022] FIGS. 12-15 show a ramp assembly load sequence;

[0023]FIG. 16 shows a partial perspective view of a roller chain of atrailer unit used to engage a corresponding part on a ramp assembly,

[0024]FIG. 17 shows a partial perspective view of a bracket arrangementon a trailer unit used to engage a corresponding bracket on a rampassembly when the ramp assembly is loaded on the trailer unit; and

[0025]FIG. 18 shows a top plan view of a front part of the ramp assemblyconnected to a tongue member to facilitate connection to a trailer hitch

DETAILED DESCRIPTION

[0026] Referring to FIG. 1, an exploded, partial perspective view of oneembodiment of an adjustable access ramp assembly 10 is shown andincludes a frame 12 formed by a ground part 14 and a raised part 16having a landing/switchback platform 18 thereon. Applicable codes mayrequire such a level rest area 18 after a certain ramp distance. It iscontemplated that the frame 12 will be formed of suitable materials toprovide required stability and load bearing capabilities. In oneembodiment steel rods, beams and tubes are used, but it is recognizedother materials could also be used. In final construction, the raisedpart 16 is rigidly connected with the ground part 14 by welding or anyother suitable fastening technique. A ramp unit 20 has an end 22adjacent the platform 18. The ramp unit 20 is movably mounted to theframe 12 to permit end 24 of the ramp unit to be positioned either (i)above the landing/platform 18 such that the ramp unit 20 leads down tothe landing/platform or (ii) below the landing/platform 18 such thatthat ramp unit 20 leads up to the landing/platform 18. A second, similarramp unit 26 is positioned alongside ramp unit 20 and has its end 28adjacent the landing/platform 18 and is likewise movably mounted to theframe 12 to permit end 30 of the ramp unit 26 to be positioned either(i) above the landing/platform 18 such that the ramp unit 26 leads downto the landing/platform or (ii) below the platform 18 such that thatramp unit 26 leads up to the landing/platform 18. In an alternativeembodiment the ramp units 20 and 26 may connect to opposite sides of theplatform 18.

[0027] In one embodiment, each ramp unit may have a length of between 15and 20 feet and a width of between 3 and 5 feet, the platform may have adepth (e.g., from the side adjacent to the ramp units to the oppositeside) of between 3 and 6 feet and a width of between 6 and 10 feet, theplatform 18 may be at a height of between 12 and 24 inches above thebottom of the frame 12, and the ground part 14 of the frame, inclusiveof platform depth, may have a length of between 15 and 20 feet. However,it is recognized that many different sizes of the ramp assembly arepossible and useful, the above dimensions being exemplary only.

[0028] Each ramp unit 20 and 26 includes respective spaced apartrailings 32 and 34 and a respective rampway or ramp surface 36 and 38positioned therebetween. The ramp units 20 and 26 may include respectivesteel frames to which the railings and the ramp surface are attached. Inone embodiment, the railings 32 and 34 may be formed of steel and therampways 36 and 38 may be formed of aluminum plate-type material withthe surfaces thereof worked to provide suitable traction. The railings32 and 34 may include hand rails 40 and 42 at intermediate heights tofacilitate grasping by children or persons in wheelchairs, the rails 40and 42 including respective u-shaped end sections 44 and 46. Notably,each rampway 36 and 38 can include a respective exit/entry segment 48and 50 that is pivotally connected to the rest of the rampway to aid inachieving a flush transition to ground level or to platform level.

[0029] Referring now to FIGS. 2A-2D, schematic illustrations ofalternative installation configurations for the ramp assembly 10 areshown. In the installation configuration of FIGS. 2A (top plan view) and2B (perspective view), the ramp unit 20 is positioned with end 24 abovethe platform 18 and adjacent a platform 300 and associated steps 302that service a door 304 located toward a right side of a modular housingunit 306. Ramp unit 26 is positioned with end 30 below the platform 18on the ground. In the installation configuration of FIGS. 2C (top planview) and 2D (perspective view), the ramp unit 20 is positioned with end24 below the platform 18 and on the ground, and ramp unit 26 ispositioned with end 30 above the platform 18 and adjacent a platform 310and associated steps 312 that service a door 314 located toward a leftside of a modular housing unit 316. Thus, the illustrated ramp assembly10 can be installed in alternative configurations as may be needed atdifferent installation sites, or to facilitate access to different entrydoors of a modular housing unit, increasing the versatility of the rampassembly 10.

[0030] Referring again to FIG. 1, the switchback platform 18 includes arail system 51 as needed for safety. The illustrated rail system 51includes end rail unit 52 and lateral rail units 54 and 56. End railunit 52 may be removably or permanently connected to the edge of theplatform 18. Notably, lateral rail units 54 and 56 are of slightlydifferent configurations. Both rail units 54 and 56 include spaced apartmount projections 58 and 60 at the bottom thereof for insertion intocorrespondingly spaced apart mount openings (not shown) formed at thelateral edges of the platform 18. Rail unit 54 includes one end that isdefined by a substantially vertical rail rod/tube 62 and an opposite endthat is defined by a rail rod/tube 64 that inclines inwardly from top tobottom. Rail unit 56 includes one end that is defined by a substantiallyvertical rail rod/tube 66 and an opposite end that is defined by a railrod/tube 68 that inclines outwardly from top to bottom. Each rail unitcan be positioned at either of the lateral side locations of theplatform 18 as needed. In particular, when the access ramp assembly isinstalled with the end 30 of ramp unit 26 in the raised position and theend 24 of ramp unit 20 in its lowered position (as shown in FIGS. 2C and2D), the rail unit 56 is positioned at the location adjacent the end 28of ramp unit 26 and the rail unit 54 is positioned at the locationadjacent the end 22 of ramp unit 20. Alternatively, when the access rampassembly is installed with the end 30 of ramp unit 26 in the loweredposition and the end 24 of ramp unit 20 in its raised position (as shownin FIGS. 2A and 2B), the rail unit 56 is positioned at the locationadjacent the end 22 of ramp unit 20 and the rail unit 54 is positionedat the location adjacent the end 28 of ramp unit 26. The angled natureof rail rod/tube 64 helps avoid excessive gaps when positioned adjacentthe outwardly inclined (from bottom to top and relative to the platform)end rail/tube of whichever ramp unit leads upward to the platform 18 andthe angled nature of rail rod/tube 68 helps avoid excessive gaps whenpositioned adjacent the inwardly inclined (from bottom to top andrelative to the platform) end rail/tube of whichever ramp unit leadsdownward to the platform 18.

[0031] Also of note in FIG. 1 is that the ground part 14 of frame 12 mayinclude a plurality of height adjustment mechanisms 70. In theillustrated embodiment four are provided, one at each corner of theframe. While any type of height adjustment mechanism might be used, inone embodiment it is contemplated that the height adjustment mechanismsare formed by support feet 72 threadedly connected to the flame viascrews 74 so that the support feet are simply rotated to produceleveling of the platform 18. One or more level indicators could also beintegrated onto the frame 12 in order to facilitate such leveling.

[0032] In order to facilitate adjustment of the ramp assembly, theillustrated embodiment includes integrated jack mechanisms 80 and 82 formoving the ramp units 20 and 26 respectively. The term “integrated jack”is intended to refer to a jack that is connected to the ramp assemblyand that remains connected with the ramp assembly during normal use ofthe ramp assembly. In particular, and referring to both jack mechanisms80 and 82 using similar component numbering, the hydraulic jack unitsinclude a stationary cylinder portion 84 and a moving rod portion 86,but it is recognized that other types of jack mechanisms could be used.The end of the moving rod portion 86 is pivotally connected to a liftframe 88 with a lower rod part 90, the sides of which ride in U-shapedtracks 92, and an upper part 94 that pivotally connects to the undersideof the ramp unit. When the frame is level, the tracks 92 may angleslightly upwardly (moving from right to left in FIG. 1).

[0033] When an integrated jack is in a retracted position, as per jackmechanism 80, the lift frame 88 is positioned to place part 94 in alowered condition to lower its ramp unit. When an integrated jack is inan extended position, as per jack mechanism 82, the lift frame 88 ispositioned to place part 94 in the raised condition to raise its rampunit. The cylinder portion 84 of each jack mechanism is provided with amanual hand crank 96 to control the jack, enabling each ramp unit 20 and26 to be adjusted to a plurality of different positions as needed tofacilitate use of the ramp assembly 10 at a variety of differentinstallation locations having varying conditions. The integrated jackmechanisms 80 and 82 also aid in supporting the respective ramp units 20and 26 in their final positions when installed, and therefore act as ameans for supporting the ramp units in a plurality of orientationsrelative to the platform. A removable or pivotally connected stand unit150 having adjustable height might additionally be provided,particularly for use in supporting the ramp unit that is placed in theupper position upon installation. In such cases, the stand unit 150 alsoacts as a means for supporting the ramp unit in a plurality oforientations relative to the platform.

[0034] While the use of jack mechanisms that are integrated with theassembly is illustrated and preferred, it is also recognized that theassembly could be adjusted using a portable jack mechanism. In such anembodiment, the frame 12 could be provided with suitable ramp unitsupports to which the ramp units can be fixed, such as side locatedupright frame supports with a plurality of vertically spaced openings orslots through which a laterally extending rod or rods can be positionedto support the ramp unit when it reaches its install position. Fasteners(e.g., nut and bolt assemblies) could also be used in place of thelaterally extending rod or rods. In such embodiments, such structurewould act as one means for supporting the ramp units in a plurality oforientations relative to the platform. It is also recognized that insome embodiments both the integrated jack mechanisms and theaforementioned side located upright frame supports with a plurality ofvertically spaced openings or slots could be used in combination.

[0035] Referring now to FIG. 3, a frame 12′ having a constructionslightly different than that depicted in FIG. 1 is shown. The groundpart 14′ of the frame 12′ is formed by rectangular steel side tubes 100and 102 connected by a square steel lateral tube 104 at one end. Theside tubes 100 and 102 are also connected by the platform supporting,laterally extending steel plates 106-116 that are welded thereto. Acenter steel I-beam 118 is also provided, with steel plates 106-116 alsobeing welded thereto. A rectangular steel lateral tube 120 also extendsbetween the side tubes 100 and 102. A center square steel tube 121extends between lateral tube 120 and lateral tube 104.

[0036] As shown, the upper sides of steel plates 108-114 are formed witha plurality of notches 123 therein to receive a plurality of supportribs. An exemplary side support rib 122 is shown and includes topopenings 124 that can be used to receive the projecting parts of one ofthe rail units 54, 56. An exemplary intermediate support rib 126 is alsoshown. The lower sides of the steel plates 106-116 are formed withlateral cutouts 128 that will permit wheels of a wheeled trailer unit topass therethrough as will be described in greater detail below. Asshown, slight cutouts are also provided in the bottom sides of plates106-116 to facilitate the rods 86 of the jack mechanisms 80 and 82. Thelateral tube 120 includes openings 130 to permit passage of the rods 86therethrough.

[0037] The lift frames 88′ include side links 132 connected by laterallyextending rods 134, 136 and 138. Rollers 140 are provided at the ends ofrod 138 for riding in the side tracks 92. A central bracket 142 connectsrods 134, 136 and 138 and the jack rod 86 is pivotally connected to thecentral bracket 142.

[0038] In some cases it may be helpful to use a counter-bias inconnection with the integrated jack mechanisms. In one example,referring to jack mechanism 80 of FIG. 3, a plate 190 is fixed at anintermediate location along the rod 86 and a pair of gas springs 192 arepositioned between the plate 190 and lateral tube 120. When the jackmechanism 80 is in its retracted position as shown, the lift frame 88′and its associated ramp unit (not shown) is in its down position, andthe gas springs 192 are in a noncompressed state. If the jack mechanism80 is adjusted to its extended position (e.g., the position illustratedfor jack mechanism 82) the gas springs 192 become compressed. Suchcompression of the gas springs 192 exerts a bias that tends to urge thejack mechanism 80 into its non-extended position so that when thehydraulic pressure in cylinder 84 is reduced, the gas springs 192 willaid in bringing the ramp unit down. The jack mechanism 82 may include asimilar gas spring arrangement (not shown). It is also recognized thatin some cases other types of biasing mechanisms may be used in place ofthe gas springs 192.

[0039] Each side tube 100 and 102 includes a respective, stowedstabilizer rod 144 that can be pulled outward for use in transport ofthe ramp assembly as will be described in greater detail below. The endof each stabilizer rod 144 includes a respective pin 146 or otherprojecting part that prevents the rod from being taken completely out ofthe tube and off of the frame 12. The stabilizer rods represent onemeans for connecting the ramp assembly to a trailer hitch. Brackets 152and 154 are also provided to facilitate connection of an extension part155 that is stowed in tube 121 for use in connecting to a vehicle fortransport, again as will be described in greater detail below. As analternative to the brackets 152 and 154, the tube 121 could include aplurality of openings that can be aligned with corresponding openings onthe extension part 155 to permit fasteners to pass therethrough. Theextension part 155 may also be formed as a steel tubular member. Theextension part 155 represents another means for connecting the rampassembly to a trailer hitch.

[0040] Referring now to FIGS. 4-8, a detailed description of oneembodiment for providing pivotal attachment of the ramp units to theraised platform/landing. FIG. 4 shows a partially exploded view of onecorner portion of ramp unit 26, including rampway 38. As shown, the endof the rampway panel is stitch welded at 160 to a lateral tube 162. Thisconstruction helps prevent warping or buckling of the end of the rampway38. An end of the tube 162 is aligned with a tubular part 164 extendingfrom a side support 166 of the ramp unit. Various railing pieces arealso shown. As best seen in the partial end elevation of FIG. 5, the endof lateral tube 162 is spaced apart from the end of tubular part 164forming a gap therebetween.

[0041]FIG. 6 shows one corner of the platform part 16 of the frame,including platform 18 positioned thereon. On a side of plate 106 a pairof brackets mount a tubular part 170 that is sized to fit into the gapbetween tube 162 and tubular part 164. When the ramp unit 26 isconnected to the platform the tubular part 170 is placed between tube162 and tubular part 164 (as shown in the end elevation of FIG. 7) and arod 172 (FIG. 8) is passed therethrough to form a hinge. A similararrangement 174 is provided on the other side of the ramp unit tocomplete the hinge, allowing the ramp unit to pivot relative to theraised platform. The primary support for the end of the ramp unit isprovided between tubular parts 164, tubular parts 170 and rod/pin 172.

[0042]FIG. 9 illustrates a partial cross-section of the ramp unit whenpositioned adjacent the raised platform 18. As shown, an L-bracket 176is fixed to the side of plate 106 and is positioned to extend to thetube 162 for alignment with the end of the rampway 38. A slight gap isprovided between the end of rampway 38 and the end of the horizontalpart of bracket 176, sufficient to facilitate movement of the rampway 38as needed during pivot, but small enough to prevent any trip hazard.Thus, the horizontal part of bracket 176 essentially acts as part of theplatform 18 and the end of the rampway 38 is considered to be positionedadjacent the edge of the platform. The bracket 176 might be welded toplate 106, or could be mounted thereto using nut and bolt arrangementsto provide for some adjustability. During pivot the height of the end ofthe rampway 38 preferably remains at a height substantially the same asthe height of the platform 18 (i.e., a difference in elevation betweenthe two does not exceed ½″). Where the variation in height exceeds adesired limit, a moving transition plate or cover may be placed betweenthe edge of the platform and the edge of the rampway, and may partiallycover both, in order to accommodate such changes.

[0043] Referring now to FIG. 10, an exemplary wheeled trailer unit 200for use in hauling the adjustable ramp assembly 10 is shown. The unit200 includes a central part 202 and a lateral part 204. Each end of thelateral part 204 is provided with a wheel assembly, including both aninner and outer wheel (not shown), for permitting the unit to roll. Thecentral part 202 includes guide angles 206 that are fixed in spacedapart relation to form a gap 208 therebetween. Front guide angles 206and rear guide angles 210 are shown, both fixed to lateral frame parts212, but it is recognized that a single, longer guide angle could besubstituted for each guide angle pair 206, 210. At the side of onelateral frame part 212, a roller chain 214 extends between sprockets 216and 218, both shown separated from respective shafts 220 and 222. Shaft222 represents the chain drive shaft that extends from a gearbox 224which is driven by a rotatable hand crank 226, allowing the roller chain214 to be moved in either direction. Notably, extending between theguide angles 206 and 210 are a plurality of rollers 228 mounted onrespective roller pins 230. Wear strips 232, which may be formed of highdensity polymer, are provided on the underside of the lateral part ofeach guide angle 206 and 210. As best seen in the partial end elevationof FIG. 11, the result provides a laterally extending slot 234 betweenthe rollers 228 and wear strips 232, the use of which will becomeapparent below.

[0044] The lateral part 204 of the trailer unit may be formed in part byfront 240 and rear 242 steel tubes. Ramped supports 244 are connected toangles 246 located toward the ends of the lateral part 204, with thespacing between supports 244 being matched to a spacing betweencorresponding support flats provided on the underside of the ground part14 of the ramp assembly frame 12. The ramped supports 244 includerollers 248 at the high sides thereof. Angles 250 and 252 are used asinner axle mounts for the wheel assemblies. A bracket arrangement 254 isprovided for locking the trailer unit 200 to the ramp assembly 10 duringtransport. The ramp assembly is loaded onto the trailer unit 200 fortransport as will now be described with reference to FIGS. 12-17.

[0045] The wheeled trailer unit 200 is positioned with its open,unobstructed end near the edge of the end of the platform 18 as shown inFIG. 12. A pair of jacks 260 are then positioned at the sides of theramp assembly 10 and are used to raise the ramp assembly into theinclined position shown in FIG. 13. The side portions of the rampassembly may include respective, integrated trailer jack mounts (e.g.,typically laterally extending tubular extensions for engagingcorresponding later tubular parts on the jack) to facilitate this step.Another jack 262, which is wheeled at the bottom thereof is positionedtoward the end of the trailer unit 200, which may also have anintegrated trailer jack mount and the jack 262 is used to lift thetrailer unit so that its angle substantially matches that of the rampassembly 10. The trailer unit 200 is then moved toward the ramp assembly10 such that the lower part of the ramp assembly I-beam 118 moves intothe slot 234 (FIG. 10) formed at the end of the trailer unit 200, withthe central part of the I-beam sticking up between the gap 208. Thus,the lower part of the I-beam 118 acts as one means for connecting theramp assembly 10 to the trailer unit 200. After the I-beam is partiallyengaged in the slot 234, the roller chain 214 of the trailer unit isconnected to the ramp assembly 10. In this regard, reference is made toFIG. 16 which shows how such an attachment can be made. In thisillustrated embodiment, the roller chain 214 is modified to include apair of links 264 extending therefrom and the underside of the platformincludes connecting blocks 266 extending therefrom. The openings in thefreed ends of the links 264 are aligned with the openings in theconnecting blocks 266 and a pin (not shown) is passed therethrough.Thus, the connecting blocks 266 act as another means for connecting theramp assembly 10 to the trailer unit.

[0046] After the chain 214 is connected to the ramp assembly 10, thecrank 226 is rotated to move the chain in a direction to pull thetrailer unit 200 and ramp assembly 10 together. As shown in FIG. 14, dueto the weight of the larger ramp assembly 10 and the wheeled nature ofthe trailer unit 200, the trailer unit 200 is actually pulled beneaththe ramp assembly 10 as the crank is rotated, rolling on wheels 275 asit does so. During movement of the trailer unit 200 the ramp assemblyrides up the supports 244 (FIG. 10) and then along the rollers 248. Asthe trailer unit 200 is pulled under the ramp assembly 10, the bracketarrangement 254 aligns with a corresponding bracket 270 on the rampassembly (see partial view of FIG. 17) and a pin (not shown) is passedthrough the aligned openings to lock the ramp assembly 10 in place onthe trailer unit 200. The jack 262 can then be removed. Thus, thebracket 270 acts as another means for connecting the ramp assembly 10 tothe trailer unit 200.

[0047] Once the ramp assembly 10 is loaded onto the trailer unit 200,extension part 155 is moved to its extended position and connected tobrackets 154 (FIG. 3). A tongue member 272, configured at one end forconnecting to a trailer hitch of a vehicle, is then connected to theextension part 155. The tongue member 272 may be the same tongue memberuse to transport the trailer unit 200 when there is no ramp assembly 10connected to the trailer unit 200, the gearbox end of the trailer unit200 including structure for securing the tongue member 272 thereto. Oncethe tongue member 272 is connected to the extension part 155 and thensupported on a vehicle trailer hitch, jacks 260 can be removed. Thestabilizer rods 144 are pulled from there stowed positions and thenconnected to the tongue member 272 as shown in FIG. 18, which is a topplan view of the front part of the loaded ramp assembly. The rampassembly 10 can then be hauled to any desired location. In oneembodiment, the ramp units are positioned with their free ends in theirrespective raised positions during hauling.

[0048] Unloading the ramp assembly 10 from the trailer unit 200 isessentially a reverse of the loading operation. Once unloaded, theheight adjustment mechanisms 70 can be used to level the platform 18,and then the two ramp units can be moved (e.g., by using the integratedjacks 20 and 26) so that one ramp unit leads from a lower elevation upto the platform 18 and the other ramp unit leads from an upper elevationdown to the platform 18. The rail units 54 and 56 are then positioned inthe appropriate locations on the sides of the platform 18. It is alsorecognized that in certain installations the free end of both ramp unitsmight be positioned at elevations that are both lower than the platform18.

[0049] To provide an alternative transport technique, the platform endof the ramp assembly may be provided with rollers at the bottom sidesthereof to facilitate loading and unloading of the ramp assembly on atilt-bed type truck, trailer or other equivalent.

[0050] It is to be clearly understood that the above description isintended by way of illustration and example only and is not intended tobe taken by way of limitation. Various changes and modifications couldbe made. For example, in certain applications a ramp assembly having asingle, movable ramp unit might be provided. Other changes andmodifications could be made, including both narrowing and broadeningvariations and modifications of the appended claims.

What is claimed is:
 1. An adjustable access ramp assembly for providingramped access between two elevations, the assembly comprising: a frameincluding a raised switchback platform; a first ramp unit having a firstend positioned adjacent the switchback platform and a second endpositioned away from the switchback platform, the first end of the firstramp unit mounted for pivotal movement to permit its second end to movebetween a plurality of heights relative to the switchback platform; anda second ramp unit, alongside the first ramp unit, and having a firstend positioned adjacent the switchback platform and a second endpositioned away from the switchback platform, the first end of thesecond ramp unit mounted for pivotal movement to permit its second endto move between a plurality of heights relative to the switchbackplatform.
 2. The access ramp assembly of claim 2, further comprising: arail system including at least a first rail unit mountable on theswitchback platform in either of first and second locations and a secondrail unit mountable on the switchback platform in either of the firstand second locations.
 3. The access ramp assembly of claim 2 wherein:the first rail unit and second rail unit are of differentconfigurations; the first amp unit pivots to position its second end inat least both a lowered position relative to the switchback platform anda raised position relative to the switchback platform; the second rampunit pivots to position its second end in at least both a loweredposition relative to the switchback platform and a raised positionrelative to the switchback platform; when the access ramp assembly isinstalled with the first ramp unit second end in its raised position andthe second ramp unit second end in its lowered position, the first railunit is positioned at the first location adjacent the first ramp unitfirst end and the second rail unit is positioned at the second locationadjacent the second ramp unit first end; and when the access rampassembly is installed with the first ramp unit second end in its loweredposition and the second ramp unit second end in its raised position, thesecond rail unit is positioned at the first location adjacent the firstramp unit first end and the first rail unit is positioned at the secondlocation adjacent the second ramp unit first end.
 4. The access rampassembly of claim 1, further comprising: a first integrated jack forraising and lowering the first ramp unit second end; and a secondintegrated jack for raising and lowering the second ramp unit secondend.
 5. The access ramp assembly of claim 4 wherein: the firstintegrated jack includes a fixed part connected to the frame and amovable part connected to the first ramp unit; the second integratedjack includes a fixed part connected to the frame and a movable partconnected to the second ramp unit.
 6. The access ramp assembly of claim5 wherein: the movable part of the first integrated jack includes afirst rod pivotally connected to a first lift frame, the first liftframe pivotally connected to the first ramp unit; the movable part ofthe second integrated jack includes a second rod pivotally connected toa second lift frame, the second lift frame pivotally connected to thesecond ramp unit.
 7. The access ramp assembly of claim 4 wherein: thefirst integrated jack comprises a hydraulic unit; and the secondintegrated jack comprises a hydraulic unit.
 8. The access ramp assemblyof claim 1 wherein: the first ramp unit includes spaced apart side railswith a rampway therebetween; and the second ramp unit includes spacedapart rails with a rampway therebetween.
 9. The access ramp assembly ofclaim 8 wherein the first end of the first ramp unit rampway maintains asubstantially even height with the switchback platform regardless ofposition of the first ramp unit second end and the first end of thesecond ramp unit rampway maintains a substantially even height with theswitchback platform regardless of position of the second ramp unitsecond end.
 10. The access ramp assembly of claim 1, wherein: the firstramp unit pivots to position its second end in at least both a loweredposition relative to the switchback platform and a raised positionrelative to the switchback platform; and the second ramp unit pivots toposition its second end in at least both a lowered position relative tothe switchback platform and a raised position relative to the switchbackplatform.
 11. The access ramp assembly of claim 1 wherein: the frameincludes a plurality of height adjustment mechanisms for leveling theswitchback platform on uneven ground.
 12. The access ramp assembly ofclaim 10 wherein: a multiplicity of the height adjustment mechanismscomprise support feet threaded onto the frame to permit adjustment viarotation.
 13. The access ramp assembly of claim 1, further comprising:at least one means for supporting the first ramp unit in a plurality oforientations relative to the platform; at least one means for supportingthe second ramp unit in a plurality of orientations relative to theplatform.
 14. An adjustable access ramp assembly for providing rampedaccess between two elevations, the assembly comprising: a frameincluding a raised platform; a first ramp unit including a rampwayhaving a first end positioned adjacent the platform and a second endpositioned away from the platform, the first ramp unit movably mountedto the frame to enable its second end to move between a plurality ofheights relative to the platform while the first end of the rampwayremains at a height substantially the same as a height of the platform;a second ramp unit including a rampway having a first end positionedadjacent the platform and a second end positioned away from theplatform, the second ramp unit movably mounted to the frame to enableits second end to move between a plurality of heights relative to theplatform while the first end of the rampway of the second ramp unitremains at a height substantially the same as the height of theplatform.
 15. The access ramp assembly of claim 14, further comprising:at least one jack connected for moving the first and second ramp units.16. The access ramp assembly of claim 15 wherein the jack comprises anintegrated hydraulic unit.
 17. The access ramp assembly of claim 15wherein: the at least one jack comprises a first integrated jack formoving the first ramp unit and a second integrated jack for moving thesecond ramp unit.
 18. The access ramp assembly of claim 15 wherein: theframe includes a plurality of height adjustment mechanisms for levelingthe platform of uneven ground.
 19. The access ramp assembly of claim 14,further comprising: a platform rail system including at least a firstrail unit mountable on the platform in either of first and secondlocations and a second rail unit mountable on the platform in either ofthe first and second locations, the first rail unit and second rail unitare of different configurations.
 20. The access ramp assembly of claim14 wherein the first ramp unit is positioned alongside the second rampunit and the platform comprises a switchback platform.
 21. An adjustableaccess ramp assembly for providing ramped access between two elevations,the assembly comprising: a frame including a platform; a first ramp unithaving a first end adjacent the platform, the first ramp unit movablymounted to the frame to permit a second end of the first ramp unit to bepositioned either (i) above the platform such that the first ramp unitleads down to the platform or (ii) below the platform such that thatfirst ramp unit leads up to the platform; and a second ramp unit havinga first end adjacent the platform, the second ramp unit movably mountedto the frame to permit a second end of the second ramp unit to bepositioned either (i) above the platform such that the second ramp unitleads down to the platform or (ii) below the platform such that thatsecond ramp unit leads up to the platform.
 22. The access ramp assemblyof claim 21 wherein: a plurality of height adjustment mechanisms areassociated with the frame for leveling the platform on uneven ground.23. The access ramp assembly of claim 21, further comprising: a firstintegrated jack for raising and lowering the first ramp unit second end;and a second integrated jack for raising and lowering the second rampunit second end.
 24. The access ramp assembly of claim 21, furthercomprising: at least one means for supporting the first ramp unit in aplurality of orientations relative to the platform; at least one meansfor supporting the second ramp unit in a plurality of orientationsrelative to the platform.
 25. The access ramp assembly of claim 21,further comprising: at least one means for connecting the ramp assemblyto a wheeled trailer unit.
 26. The access ramp assembly of claim 21,further comprising: at least one means stowed on the ramp assembly forconnecting the ramp assembly to a trailer hitch.
 27. An adjustableaccess ramp assembly for providing ramped access between two elevations,the assembly comprising: a platform; a ramp unit including a rampwaysurface having a first end positioned adjacent the platform and a secondend positioned away from the platform, the ramp unit pivotally mountedadjacent to the platform
 28. The adjustable access ramp assembly ofclaim 27, further comprising: an integrated jack for moving one of theramp unit and the platform to adjust an incline of the rampway surfacerelative to the platform.
 29. The access ramp assembly of claim 28,wherein the platform comprises a raised part of a frame and theintegrated jack is positioned between the frame and the ramp unit topivot the ramp unit to adjust a height of the second end of the rampwaysurface relative to the platform.
 30. The access ramp assembly of claim28 wherein the first end of the rampway surface remains at a heightsubstantially the same as a height of the platform during pivot of theramp unit.
 31. The access ramp assembly of claim 28 wherein: theintegrated jack includes a rod pivotally connected to a lift frame, thelift frame pivotally connected to the ramp unit.
 32. The access rampassembly of claim 27 wherein the ramp unit comprises a first ramp unitand the access ramp assembly further includes: a second ramp unitincluding a rampway surface having a first end positioned adjacent theplatform and a second end positioned away from the platform, the secondramp unit pivotally mounted adjacent to the platform.
 33. The accessramp assembly of claim 27 wherein: a plurality of height adjustmentmechanisms are associated with the platform for leveling the platform onuneven ground.
 34. The access ramp assembly of claim 27, furthercomprising: at least one means stowed on the ramp assembly forconnecting the ramp assembly to a trailer hitch.
 35. The access rampassembly of claim 27, further comprising: at least one means forconnecting the ramp assembly to a wheeled trailer unit.
 36. The accessramp assembly of claim 27, further comprising: a rail system includingat least two removable rail units connectable at sides of the platform.37. A method of providing ramped access between first and seconddifferent elevations, the method comprising the steps of: providing anadjustable access ramp assembly including a frame having a raisedplatform, a first ramp having first and second ends, the first rampmovably mounted to the frame with its first end adjacent the platform,and a second ramp having first and second ends, the second ramp movablymounted to the frame with its first end adjacent the ramp platform;positioning the adjustable access ramp assembly at a site of the firstand second different elevations; adjusting the frame such that theraised platform is substantially level; positioning the first ramp suchthat its second end is positioned lower than the platform, at the firstelevation, and the first ramp leads up to the platform; and positioningthe second ramp such that its second end is positioned higher than theplatform, at the second elevation, and the second ramp leads down to theplatform.
 38. The method of claim 37, comprising the further steps of:the access ramp assembly positioning step involves: connecting theadjustable access ramp assembly to a wheeled trailer; hauling theadjustable access ramp assembly to the site using the wheeled trailer;disconnecting the adjustable access ramp assembly from the wheeledtrailer at the site.
 39. The method of claim 38 wherein the connectingstep involves the use of stowed stabilizer bars within the frame, thestabilizer bars movable to a position extending from the frame.
 40. Themethod of claim 38 wherein the connecting and disconnecting stepsinvolve the use of a chain unit on the wheeled trailer.
 41. The methodof claim 38 wherein during the hauling step the second end of the firstramp is positioned higher than the platform and the second end of thesecond ramp is positioned higher than the platform.
 42. The method ofclaim 37 wherein the step of positioning the first ramp involvesutilization of a first integrated jack provided on the adjustable accessramp assembly and the step of positioning the second ramp involvesutilization of a second integrated jack provided on the adjustableaccess ramp assembly.
 43. A method of providing ramped access betweenfirst and second different elevations, the method comprising the stepsof: providing an adjustable access ramp assembly including a framehaving a raised platform, and a ramp having first and second ends, theramp movably mounted to the frame with its first end adjacent theplatform; connecting the adjustable access ramp assembly to a wheeledtrailer; hauling the adjustable access ramp assembly to the site usingthe wheeled trailer; disconnecting the adjustable access ramp assemblyfrom the wheeled trailer at a site of the first and second differentelevations; adjusting the frame such that the raised platform issubstantially level.
 44. The method of claim 43 wherein the connectingstep involves the use of stowed stabilizer bars within the frame, thestabilizer bars movable to a position extending from the frame.
 45. Themethod of claim 43 wherein the connecting step involves aligning atleast one frame support member with a correspondingly shaped receivingstructure on the wheeled trailer and engaging the frame support memberwith the receiving structure.
 46. The method of claim 43 wherein theconnecting step involves connecting a chain on the wheeled trailer to aportion of the adjustable access ramp assembly and operating a chaincrank to move the chain and pull the wheeled trailer underneath theadjustable access ramp assembly.
 47. The method of claim 43 wherein theadjusting step involves the use of a plurality of height adjustmentmechanisms incorporated on the frame.
 48. A trailer unit adapted forhauling an access ramp assembly, the trailer unit comprising: a frameincluding central part including a slot for receiving a lower part of anaccess ramp assembly I-beam; a chain system with associated hand crankfor use in engaging the pulling the trailer unit and an access rampassembly together; spaced apart wheels connected with the frame forallowing the trailer unit to roll.
 49. The trailer unit of claim 48including spaced apart rollers on the frame for engaging respectiveaccess ramp assembly bottom surfaces.
 50. The trailer unit of claim 48wherein the slot is formed between rollers and wear strips.